Piston Ring, Engine

PISTON RING SIDE CLEARANCE





^ Measure the side clearance of piston ring and piston ring groove with a feeler gauge (A).
Standard:
Top ring: 0.04 - 0.08 mm (0.002 - 0.003 in)
2nd ring: 0.03 - 0.07 mm (0.001 - 0.003 in)
Oil ring: 0.015 - 0.185 mm (0.001 - 0.007 in)
Limit:
Top ring: 0.11 mm (0.0043 in)
2nd ring: 0.10 mm (0.0039 in)
^ If the measured value exceeds the limit, replace piston ring, and measure again. If it still exceeds the limit, replace piston also.

PISTON RING END GAP
^ Make sure that cylinder bore inner diameter is within specification.





^ Lubricate with new engine oil to piston (1) and piston ring (2), and then insert (A) piston ring until middle of cylinder (B) with piston, and measure piston ring end gap with a feeler gauge (C).
Standard:
Top ring: 0.20 - 0.30 mm (0.008 - 0.012 in)
2nd ring: 0.50 - 0.65 mm (0.020 - 0.026 in)
Oil ring (rail ring): 0.15 - 0.45 mm (0.006 - 0.018 in)
Limit:
Top ring: 0.51 mm (0.020 in)
2nd ring: 0.83 mm (0.033 in)
Oil ring (rail ring): 0.78 mm (0.031 in)
^ If the measured value exceeds the limit, replace piston ring, and measure again. If it still exceeds the limit, re-bore cylinder and use oversized piston and piston rings.